Bayesian correction of H(z) data uncertainties

We compile 41 H(z) data from literature and use them to constrain O CDM and flat CDM parameters. We show that the available H(z) suffers from uncertainties overestimation and propose a Bayesian method to reduce them. As a result of this method, using H(z) only, we find, in the context of O CDM, H 0 = 69.5 2.5 km s -1 Mpc -1 , m = 0.242 0.036, and = 0.68 0.14. In the context of flat CDM model, we have found H 0 = 70.4 1.2 km s -1 Mpc -1 and m = 0.256 0.014. This corresponds to an uncertainty reduction of up to 30 per cent when compared to the uncorrected analysis in both cases.